Rapid Drug Desensitization Protocol in Delayed Hypersensitivity Reactions to CFTR Modulator Drugs: When Every Day Counts

Small molecule cystic fibrosis transmembrane regulator (CFTR) modulator drugs have revolutionized the care of cystic fibrosis (CF) patients by targeting the underlying cause of the disease. The elexacaftor-tezacaftor-ivacaftor (ELX-TEZ-IVA) triple combination has shown significant improvements in lung function and reduced pulmonary exacerbations in CF patients. However, the risk of allergy to these drugs remains unknown. This case report presents a 9-year-old boy with CF who developed a pruritic rash after starting therapy with ELX-TEZ-IVA. Allergy testing confirmed a positive reaction to ELX-TEZ-IVA, and a rapid drug desensitization (RDD) protocol was successfully performed to enable the patient to continue CFTR modulator therapy. RDD has been shown to be a safe and effective method for patients with delayed hypersensitivity reactions to CFTR modulators, allowing them to resume therapy swiftly and minimize periods without treatment. Adequate personalized multidisciplinary management is crucial in these cases. RDD could be an effective and safe method for patients with delayed hypersensitivity reactions to CFTR modulators, enabling them to resume therapy swiftly and minimize periods without treatment.